Meta-phenoxybenzyl esters and .alpha.-cyano-m-phenoxybenzyl esters of 2-haloalkyl(oxy-, thio-, sulfinyl-, or sulfonyl)phenylalkanoic acids are known insecticidal and acaricidal agents. These compounds and methods for their preparation are disclosed in Berkelhammer et. al., U.S. Pat. Nos. 4,178,460 and 4,199,595. In both Berkelhammer et. al. U.S. Pat. Nos. 4,178,460 and 4,199,595, there is disclosed the conversion of certain .alpha.-alkyl-3(or 4)-hydroxyphenylacetic acids having the formula ##STR2## wherein R is ethyl, n-propyl or isopropyl to the corresponding .alpha.-alkyl-3(or 4)-difluoromethoxyphenylacetic acids having the formula ##STR3## wherein R is as defined above by treatment with chlorodifluoromethane in aqueous alkali and dioxane. The .alpha.-alkyl-3(or 4)-difluoromethoxyphenylacetic acids thus formed are then treated with thionyl chloride, thionyl bromide, or the like, preferably in the presence of an aromatic solvent such as benzene or toluene, to yield .alpha.-alkyl(substituted phenyl)acetyl halide which is reacted with m-phenoxybenzyl alcohol or .alpha.-cyano-m-phenoxybenzyl alcohol to yield the desired m-phenoxybenzyl ester or .alpha.-cyano-m-phenoxybenzyl ester of the 2-haloalkyl(oxy-, thio-, sulfinyl- or sulfonyl)phenylalkanoic acids which are useful insecticides. In Berkelhammer et. al., U.S. Pat. Nos. 4,178,460 and 4,199,595, the .alpha.-alkyl-3(or 4)-hydroxyphenylacetic acid intermediate is prepared by reacting the appropriate .alpha.-alkyl-3(or 4)-methoxyphenylacetonitrile with hydrobromic acid.
A new process for the synthesis of .alpha.-alkyl-4-hydroxyphenylacetic acids now has been discovered in which these materials can be prepared in a simple and straightforward manner. In this new process, 4-(.alpha.-alkyl-.alpha.-cyano-methyl)-2,6-di-substituted phenol as intermediates in a reaction sequence in which .alpha.-alkyl-4-hydroxyphenylacetic acids are likewise produced and used as reaction intermediates.
Methods are known for preparing 4-(.alpha.-alkyl-.alpha.-cyano-methyl)2,6-di-substituted phenols. For example, the preparation of 4-(.alpha.-alkyl-.alpha.-cyano-methyl)2,6-di-substituted phenol by reacting .alpha.-alkyl-4-hydroxy-3,5-di-tertiary-butylbenzyl halides with sodium cyanide is reported by A. A. Volod'kin et. al., Iz. Akad. Nauk. SSSR, Ser. Khim, 1966, 1031. Also, the preparation of 4-(.alpha.-alkyl- -cyano-methyl)2,6-di-substituted phenols by the electrochemical reduction of the corresponding 2,6-di-substituted methylenequinone is reported by L. I. Kudinova, et. al., Iz. Akad. Nauk. SSSR, Ser. Khim., 1978, 1313. In U.S. application Ser. No. 385,609, entitled "Preparation of 4-(.alpha.-Alkyl-.alpha.-Cyano-Methyl)2,6-Di-Substituted Phenol" filed on June 7, 1982, there is disclosed a novel process for the synthesis of 4-(.alpha.-alkyl-.alpha.-cyano-methyl)2,6-di-substituted phenol by reacting a 2,6-di-substituted phenol with an aliphatic aldehyde selected from formaldehyde, acetaldehyde, propionaldehyde or butyraldehyde and an alkali metal cyanide or an alkaline earth metal cyanide in a suitable reaction solvent to form the corresponding 4-(.alpha.-alkyl-.alpha.-cyano-methyl)2,6-di-substituted phenol.
The synthesis of o- and p-hydroxy substituted phenylacetonitriles also is known and is reported in the literature. See, for example, Journal of Organic Chemistry, Vol. 41, No. 14, 2502 (1976).